ACCORDING TO THE PASSAGE, IT IS BELIEVED THAT THE LARGEST EXTINCTI...

54. According to the passage, it is believed that the largest extinction of a species occurred

A. 26 million years ago

B. 65 million years ago

C. 225 million years ago

D. 250 million years ago

Read the passage and choose the best answer for each question (55-64) below.

By far the most important United States export product in the eighteenth and nineteenth

centuries was cotton,

favored

by the European textile industry over flax or wool because it was

easy to process and soft to tile touch. Mechanization of spinning and weaving allowed significant

centralization and expansion in the textile industry during this period, and at the same time the

demand for cotton increased dramatically. American producers were able to meet this demand

largely because of tile invention of the cotton gin by Eli Whitney in 1793. Cotton could be grown

throughout the South, but separating the fiber – or lint – from the seed was a laborious process.

Sea island cotton was relatively easy to process by hand, because its fibers were long and seeds

were concentrated at the base of the flower, but it demanded a long growing season, available

only along the nation's eastern seacoast. Short-staple cotton required a much shorter growing

season, but the shortness of the fibers and their mixture with seeds meant that a worker could

hand-process only about one pound per day. Whitney's gin was a hand-powered machine with

revolving drums and metal teeth to pull cotton fibers away from seeds. Using the gin, a worker

could produce up to 50 pounds of lint a day. The later development of larger gins, powered by

horses, water, or steam, multiplied productivity further.

The interaction of improved processing and high demand led to the rapid spread of the

cultivation of cotton and to a

surge

in production. It became the main American export, dwarfing

all others. In 1802, cotton composed 14 percent of total American exports by value. Cotton had a

36 percent share by 1810 and over a 50 percent share

in 1830. In 1860, 61 percent of the value of American exports was represented by cotton. In

contrast, wheat and wheat flour composed only 6 percent of the value of American exports in that

year. Clearly, cotton was king in the trade of the young republic. The growing market for cotton

and other American agricultural products led to an

unprecedented

expansion of agricultural

settlement, mostly in the eastern half of the United States---west of the Appalachian Mountains

and east of the Mississippi River.